Ah, I thought the vent sexing only worked on mature adults.
The reason I asked if the fish were wild caught or not is the prevalence of BCIR in them. Here is an excerpt from my upcoming book on that issue:
Banggai Cardinalfish Iridovirus (BCIR)
This fish was originally discovered in 1933 but then lost to science for about 60 years, when the Banggai cardinalfish (Pterapogon kauderni) was “rediscovered” and began entering the tropical fish trade. Aquarists noted how hardy the species was and that they were very easy to reproduce in captivity. A decade later, the price for wild-caught Banggai cardinalfish had decreased fivefold, but the animals were now considered very delicate, with high losses seen in newly acquired wild fish.
What was the cause of this sudden change in the apparent health of this species in captivity? Poor handling, collection with cyanide (unlikely), and bacterial disease were all suggested as possible reasons for this change. A researcher then published a study showing that the presence of an iridovirus was associated with episodes of mass mortality in newly imported cardinalfish (Weber et al. 2009). A similar virus has since been isolated from the common batfish, Platax orbicularis (Sriwanayos et al. 2013), but a corresponding high mortality in aquarium fish of that species has not been noted, perhaps because many fewer batfish are imported for the pet trade than the ever-popular Banggai cardinalfish.
Since there is no cure for this viral disease, captive-raised fish that were never exposed to wild stock, or fish that have subsequently developed immunity by surviving an infection would be the best choices for aquarists. Avoid inexpensive wild-caught Banggai Cardinalfish. Not only do they have a poor survival record, but they’re also being collected at such a high rate that wild populations are locally threatened with extinction.
Jay
